MANITOWOC ENGINEERING, CO.
Division of The Manitowoc Company, Inc. Manitowoc, Wisconsin 54220
WORM GEAR & WORM SHAFT INSPECTION
ALL MODELS
GENERAL
This folio describes and illustrates proper and improper
wear patterns between the boom or mast hoist worm
gear and worm shaft.
Inspect the wear pattern between the worm gear and
worm shaft each time the boom or mast hoist oil is
changed. If improper wear is indicated, correct the
cause for the problem.
PROPER WEAR PATTERN
(See Figure
1)
Proper wear between the worm gear and worm shaft is
indicated when the wear pattern is centered on each
tooth of the worm gear. The pattern will be smooth and
cover at least 80 percent of each tooth surface.
NOTE
The wear pattern will show up only on one side of
the gear teeth because only one side of the teeth
is loaded.
IMPROPER WEAR PATTERN
(See Figure
2)
Improper wear between the worm gear and worm shaft
is indicated when the wear pattern is shifted to one side
of the worm gear teeth. This condition will cause exces-
sive heat build-up and uneven loading resulting in the
following damage:
--Heat spots (discoloration), pitting and metal pulling
on the teeth of the worm gear.
--Heat checks, cracks, metal pulling, and erosion on
the teeth of the worm shaft.
Some conditions which cause improper wear between
the worm gear and worm shaft are listed below:
--Wrong oil in system or oil level low (see Lubrication
Guide for proper oil and level).
--Water in system. Drain water weekly (see Lubrication
Guide).
--Restriction in oil supply line to pumportoworm gear
housing.
--Faulty oil pump (not delivering oil).
©Manitowoc 1982
Smooth Pattern Centered
on 80% of Each Tooth
Surface
Figure 1
Proper Wear Pattern
Rough Wear
Pattern
Figure 2
Improper Wear Patterns
5-3-82 WORM GEAR & WORM SHAFT INSPECTION FOLIO 1097-1
395143
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